Osteotomies of the knee are an important technique for treating knee osteoarthritis. In essence, knee osteotomies adjust the geometry of the knee joint so as to transfer weight bearing load from arthritic portions of the joint to relatively unaffected portions of the joint.
Knee osteotomies are also an important technique for addressing abnormal knee geometries, e.g., due to birth defect, injury, etc.
Most knee osteotomies are designed to modify the geometry of the tibia, so as to adjust the manner in which the load is transferred across the knee joint.
There are essentially two ways in which to adjust the orientation of the tibia: (i) the closed wedge technique; and (ii) the open wedge technique.
With the closed wedge technique, a wedge of bone is removed from the upper portion of the tibia, and then the tibia is manipulated so as to close the resulting gap, whereby to reorient the lower portion of the tibia relative to the tibial plateau and hence adjust the manner in which load is transferred from the femur to the tibia.
With the open wedge technique, a cut is made into the upper portion of the tibia, the tibia is manipulated so as to open a wedge-like opening in the bone, and then the bone is secured in this position (e.g., by screwing metal plates to the bone or by inserting a wedge-shaped implant into the opening in the bone), whereby to reorient the lower portion of the tibia relative to the tibial plateau and hence adjust the manner in which load is transferred from the femur to the tibia.
While both closed wedge osteotomies and open wedge osteotomies provide substantial benefits to the patient, they are procedurally challenging for the surgeon. Among other things, with respect to open wedge osteotomies, it can be difficult to create the wedge-like opening in the bone with the necessary precision and with a minimum of trauma to the surrounding tissue (e.g., the neurological and vascular structures at the back of the knee). Furthermore, with open wedge osteotomies, it can be difficult to stabilize the upper and lower portions of the tibia relative to one another and to maintain them in this position while healing occurs.
The present invention is directed to osteotomies in bone, and is intended to provide increased precision and reduced trauma when creating the opening in the bone, and to provide increased stability to the upper and lower portions of the bone while healing occurs.